u.s. justice department is suing standard and poor's for its alleged role in the 2008 financial crisis. wall street investors say they were expecting the move. in 2007, the ratings agency made its fortune by giving high credit ratings to worthless mortgage debt. that debt later plunged in value, fuelling the crisis. standard and poor's denies the charges and has promised a vigorous defense. the u.s. justice department is charging. we go for more on the story. >> a green light from standard and poor's was once thought to be a mark of confidence, but that was before the company was caught out, giving glowing ratings to investments that bottomed out. u.s. authorities say s&p ignored the risks and misled investors. during the real-estate boom in the united states, banks were happy to sell mortgages to people who actually could barely afford them. that debt was bundled into bonds with other investments, and s&p gave them safe ratings in the financial markets. that is why investors snapped them